Analysis of the histology of the scar bladder and biochemical parameters of rats with a solitary kidney undergoing immunosuppression with tacrolimus

Denosumab-related osteonecrosis of the jaw after tooth extraction and the effects of a short drug holiday in cancer patients: a multicenter retrospective study

Pre-existing inflammation, corticosteroid therapy, periapical periodontitis, longer duration of denosumab therapy, and female sex were significantly associated with an increased risk of denosumab-related osteonecrosis of the jaw after tooth extraction in patients with cancer on oncologic doses of denosumab. A short drug holiday did not protect against this complication.

INTRODUCTION

This study retrospectively investigated the relationship between various risk factors, including brief discontinuation of denosumab, and development of denosumab-related osteonecrosis of the jaw (DRONJ) after tooth extraction in patients with cancer who were receiving oncologic doses of this agent.

METHODS

Data were collected on demographic characteristics, duration of denosumab therapy, whether or not denosumab was discontinued before tooth extraction (drug holiday), duration of discontinuation, presence of pre-existing inflammation, and whether or not additional surgical procedures were performed. Risk factors for DRONJ after tooth extraction were evaluated by univariate and multivariate analyses.

RESULTS

A total of 136 dental extractions were performed in 72 patients (31 men, 41 women) with cancer who were receiving oncologic doses of denosumab. Post-extraction DRONJ was diagnosed in 39 teeth (28.7%) in 25 patients. Tooth extraction was significantly associated with development of DRONJ only in patients with pre-existing inflammation (odds ratio [OR] 243.77), those on corticosteroid therapy (OR 73.50), those with periapical periodontitis (OR 14.13), those who had been taking oncologic doses of denosumab for a longer period (OR 4.69), and in women (OR 1.04). There was no significant difference in the occurrence of DRONJ between patients who had a drug holiday before tooth extraction and those who did not.

CONCLUSIONS

These findings suggest that inflamed teeth should be extracted immediately in patients with cancer who are receiving oncologic doses of denosumab. Drug holidays have no significant impact on the risk of DRONJ.

Risk of Delayed Healing of Tooth Extraction Wounds and Osteonecrosis of the Jaw among Patients Treated with Potential Immunosuppressive Drugs: A Retrospective Cohort Study

Bone-modifying or antiresorptive agents that target osteoclasts, such as bisphosphonates, are known to cause delayed wound healing and osteonecrosis of the jaw (ONJ) following tooth extraction. However, there are no data on whether such adverse events are also caused by drugs that may suppress the immune system, including corticosteroids, immunosuppressants, biological agents, and disease-modifying anti-rheumatic drugs (DMARDs). The aim of this retrospective study was to examine the incidence of delayed post-extraction wound healing and identify risk factors among patients treated with potential immunosuppressive drugs undergoing tooth extraction. We performed a retrospective cohort study involving 101 patients by reviewing their medical records. The underlying diseases of the enrolled patients included dilated cardiomyopathy, hematological malignancy, sarcoidosis, rheumatoid arthritis, and systemic lupus erythematosus. The sample comprised 131 cases of tooth extraction among the 101 patients; delayed post-extraction wound healing occurred in 10 patients (12 cases, 9.2%), including ONJ in three patients (3 cases, 2.3%). The surgical tooth extraction performed for impacted teeth or a residual root (P = 0.009), the number of surgical tooth extraction (P = 0.012), decreased lymphocyte counts (P = 0.008), and decreased eosinophil counts (P = 0.009) were significantly related to delayed wound healing. Thus, among patients taking corticosteroids, immunosuppressants, biological agents, and/or DMARDs, there is a risk of delayed wound healing and ONJ. Moreover, the significant risk factors are low lymphocyte counts, low eosinophil counts, and surgical extraction. It is of particular importance to prevent surgical site infection, when the high-risk patients undergo tooth extraction.

Downregulation of TRPC6 expression is a critical molecular event during FK506 treatment for overactive bladder

PURPOSE

It has been suggested that FK506 could improve some symptoms of OAB in both clinical settings and animal models; however, its mechanism of action is not well-understood. Here, we investigated the effect of FK506 on TRPC6 in bladder smooth muscle, and explored the possible involvement of TRPC6 in OAB.

METHODS

FK506 was injected intraperitoneally into rats in which OAB was induced via BOO, and urodynamic indices were recorded. Rats and human bladder smooth muscle tissues with or without OAB were examined for TRPC6 expression by western blot, RT-PCR and IF staining. Cultured BSMCs were treated with PDGF, TRPC6 siRNAs and FK506. Then the TRPC6 expression and cellular proliferation were examined, and the Ca²⁺ influx and contractility of BSMCs were examined by time-lapse Ca²⁺ imaging and collagen gel contraction. Finally, IF and Co-IP were performed to test the effects of FK506 on NFAT translocation to the nucleus and the interaction of TRPC6 with FKBP12, respectively.

RESULTS

FK506 improved urodynamic indices of OAB rats, and TRPC6 was expressed in rats and human bladder tissues. TRPC6 elevation in OAB rats was inhibited by FK506, and this inhibition coincided with improvements in urodynamic indices. PDGF enhanced TRPC6 expression, cellular proliferation, Ca²⁺ influx and contractility of BSMCs, and these effects were inhibited by TRPC6 siRNAs and FK506. FK506 inhibited NFAT translocation to the nucleus and disrupted the interaction of TRPC6 with FKBP12.

CONCLUSIONS

Our results collectively indicate that FK506 may be used to treat OAB, and that TRPC6 may serve as an attractive target for therapeutic intervention in OAB.

Immunosuppression for in vivo research: state-of-the-art protocols and experimental approaches

Almost every experimental treatment strategy using non-autologous cell, tissue or organ transplantation is tested in small and large animal models before clinical translation. Because these strategies require immunosuppression in most cases, immunosuppressive protocols are a key element in transplantation experiments. However, standard immunosuppressive protocols are often applied without detailed knowledge regarding their efficacy within the particular experimental setting and in the chosen model species. Optimization of such protocols is pertinent to the translation of experimental results to human patients and thus warrants further investigation. This review summarizes current knowledge regarding immunosuppressive drug classes as well as their dosages and application regimens with consideration of species-specific drug metabolization and side effects. It also summarizes contemporary knowledge of novel immunomodulatory strategies, such as the use of mesenchymal stem cells or antibodies. Thus, this review is intended to serve as a state-of-the-art compendium for researchers to refine applied experimental immunosuppression and immunomodulation strategies to enhance the predictive value of preclinical transplantation studies.